A healthy mixture of gut bacteria may help regulate levels of anxiety and fear-related behaviours, new research by scientists in Cork has found.
The scientists discovered that the trillions of bacteria or microbiome in the gastrointestinal tract are capable of communicating with and influencing the brain.
The researchers at the APC Microbiome Institute at University College Cork found that the gut bugs can impact brain microRNA - small molecules that influence how genes are expressed.
As a result the microRNA helps to fine tune physiological processes that are key to the operation of the central nervous system.
The study, published in the journal Microbiome, was carried out on mice and rats that had no or reduced amounts of gut microbes.
Through their experiment they were able to demonstrate that the amygdale and prefrontal cortex areas of the brain were disrupted by the changes to the microbiome.
These regions are key to the regulation of fear response, anxiety, social behaviours and other higher cognitive functions.
While it was possible to reverse some of the alterations caused by the microRNA by adding back the gut bacteria, some of the changes could not be undone.
The researchers say that this supports the concept of critical neurodevelopmental windows during which the gut microbiota is essential in influencing brain development.
It is hoped that the research, carried out by Dr Gerard Clarke and Professor John Cryan, along with their PhD student Alan Hoban, could help build knowledge around the potential use of microRNA based treatments for psychiatric illnesses.
However, much more work will be needed before such treatments would be developed and approved for treatment in humans.
"The psychobiotic revolution is coming," says Prof Cryan in a statement. "And we can now add miRNAs to an expanding range of therapeutic targets in the brain that can potentially be controlled by manipulating the bacteria in our gastrointestinal tract".
Publication of the research coincides with the APC Microbiome Institute's hosting of NeuroGASTRO 2017, the flagship meeting of the Neurogastroenterology and Motility Society attended by 400 experts in Cork.